Vehicle engines combust a mixture of air and fuel within cylinders to drive pistons and generate drive torque. Exhaust gas resulting from this combustion is then treated by an exhaust system. One or more catalysts (e.g., a three-way catalytic converter) in the exhaust system react with the exhaust gas to decrease or eliminate emissions (nitrogen oxides, carbon monoxide, hydrocarbons, etc.) released into the atmosphere. Each catalyst has a light-off period during which the catalyst heats up via the exhaust gas flowing through it. This light-off period lasts until the catalyst reaches a temperature threshold at which the catalyst can react with the exhaust gas. Therefore, longer light-off periods result in increased emissions, particularly after a cold start. Additional precious metals can be added to the catalyst to improve its performance, but this increases costs. Thus, while such exhaust system catalysts work for their intended purpose, there remains a need for improvement in the relevant art.